Minimal Arduino Clock

Making a clock with a common microcontroller like an Arduino isn’t very difficult. However, if you’ve tried it, you probably discovered that keeping track of wall time is difficult without some external hardware. [Barzok] has a very minimal clock build. It takes a handful of LED arrays with an integrated driver, an Arduino Nano, a real-time clock module, and a voltage regulator.

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Rotary Cell Phone: Blast from a Past that Never Was

The 1970s called and they want their rotary dial cell phone back.

Looking for all the world like something assembled from the Radio Shack parts department – remember when Radio Shack sold parts? – [Mr_Volt]’s build is a celebration of the look and feel of a hobbyist build from way back when. Looking a little like a homebrew DynaTAC 8000X, the brushed aluminum and 3D-printed ABS case sports an unusual front panel feature – a working rotary dial. Smaller than even the Trimline phone’s rotating finger stop dial and best operated with a stylus, the dial translates rotary action to DTMF tones for the Feather FONA board inside. Far from a one-trick pony, the phone sports memory dialing, SMS messaging, and even an FM receiver. But most impressive and mysterious is the dial mechanism, visible through a window in the wood-grain back. Did [Mr_Volt] fabricate those gears and the governor? We’d love to hear the backstory on that.

This isn’t the first rotary cell phone hybrid we’ve featured, of course. There was this GSM addition to an old rotary phone and this cell phone that lets you slam the receiver down. But for our money a rotary dial cell phone built from the ground up wins the retro cool prize of the bunch.

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Handheld Sudoku (Assuming You Have Large Hands)

[Hari Waguna] wanted to build a computerized Sudoku game. Ordinarily, that wouldn’t be a big deal. You can buy one, of course, but what fun is that? There’s plenty of apps for phones, but again, not much of a challenge. If you want to preserve your hacker cred, you’d use a CPU board like an Arduino or a Raspberry Pi with an LCD screen, right? But if you want to grow your hacker cred, you’d follow [Hari’s] lead and use 81 seven-segment displays and a membrane keyboard.

Driving that many displays takes some doing (in this case shift registers). [Hari] uses some other tricks, like reading the keyboard using a single pin (and a resistor network). He’s made several videos about the project, including the one below.

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What’s New, ESP-32? Testing the Arduino Library

In case you missed it, the big news is that a minimal Arduino core is up and working on the ESP32. There’s still lots left to do, but the core functionality — GPIO, UART, SPI, I2C, and WiFi — are all up and ready to be tested out. Installing the library is as easy as checking out the code from GitHub into your Arduino install, so that’s exactly what I did.

I then spent a couple days playing around with it. It’s a work in progress, but it’s getting to the point of being useful, and the codebase itself contains some hidden gems. Come on along and take a sneak peek.

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Litter Basket Automation

Sometimes the technology part of a project isn’t the hard part. It is having an idea for something both useful and doable. Sure, a robot butler that would do your cleaning and laundry would be useful, but might be out of reach for most of us. On the other hand, there’s only so many use cases for another blinking LED.

[Martinhui] knows how to use an ultrasonic sensor with an Arduino. Driving a motor isn’t that hard, either. The question is: what do you do with that? [Martin’s] answer: Automate a trash can. You can see a video of the result, below.

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Dual-boot Your Arduino

There was a time, not so long ago, when all the cool kids were dual-booting their computers: one side running Linux for hacking and another running Windows for gaming. We know, we were there. But why the heck would you ever want to dual-boot an Arduino? We’re still scratching our heads about the application, but we know a cool hack when we see one; [Vinod] soldered the tiny surface-mount EEPROM on top of the already small AVR chip! (Check the video below.)

aAside from tiny-soldering skills, [Vinod] wrote his own custom bootloader for the AVR-based Arduino. With just enough memory to back up the AVR’s flash, the bootloader can shuffle the existing program out to the EEPROM while flashing the new program in. For more details, read the source.

While you might think that writing a bootloader is deep juju (it can be), [Vinod]’s simple bootloader application is written in C, using a style that should be familiar to anyone who has done work with an Arduino. It could certainly be optimized for size, but probably not for readability (and tweakability).

Why would you ever want to dual boot an Arduino? Maybe to be able to run testing and stable code on the same device? You could do the same thing over WiFi with an ESP8266. But maybe you don’t have WiFi available? Whatever, we like the hack and ‘because you can’ is a good enough excuse for us. If you do have a use in mind, post up in the comments!

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Codebender Shuts Down

Codebender.cc was a cloud based IDE for Arduino development. It was made for hackers by a few fellows in Greece. Unfortunately, while they saw some serious success, they were never able to convert it all the way into a viable business.

By November 31st Codebender.cc will be completely shut down. They assure users that the site will be in read-only mode for as long as the end of the year, but longer if the traffic justifies it. Codebender made it all the way to 10,000 monthly active users, but hosting and administration overshadowed this success to the tune of 25,000 dollars a month. Not so much as far as businesses go, but without revenue it’s more than enough to shut down a site. Their business plan aimed to tailor their services for specific chip manufacturers and other companies but those deals never came together.

It’s a pity, we were excited to see if Codebender could continue to grow. They were certainly doing some really interesting stuff like remote code upload. As the comments on the site show, many users, especially educators and Chromebook users, loved Codebender — your code isn’t stuck on one computer and where there was a browser there was an IDE.

Two paid services will remain (starting at $10/month) at addresses with different TLDs. But the post does mention that the Codebender project started as Open Source. Their GitHub repo isn’t a clear path for rolling your own, but if you do manage to hack together a working Codebender implementation we’d love to hear about it.